Oral care products, such as toothpaste, are usually formulated from an aqueous base containing a structuring agent. Such structuring agent is used to tune the rheological profile of the oral care product to have special characteristics. Thus, such rheological behaviour would bring benefits to the oral care product, for example, easy manufacture process, stable oral care formulation, and easiness of squeezing for consumer use.
However, there are many ingredients used in oral care product which are physically or chemically incompatible with water. One of the solutions to this problem is to provide such ingredient in a non-aqueous oral care product.
US patent with U.S. Pat. No. 5,614,175 (Enamelon Inc.) is said to disclose a stable, single part, non-aqueous product for remineralizing lesions in tooth comprising at least one water-soluble calcium salt, and at least one water-soluble phosphate salt.
We have found that when changing from aqueous base to non-aqueous base, one of the main challenges is how to tune the rheological behaviour of the oral care composition to make it behave rheologically like an aqueous oral care composition. Such rheology would have an important impact on the manufacture, stability and consumer perception of product.
International application with publication number WO 2011/160996 (Unilever) discloses a non-aqueous oral care composition with a liquid continuous phase comprising a thickening agent, a humectant, and one or more liquid polyethylene glycols having a melting point below 25° C., in which the liquid continuous phase is structured with crystals of one or more solid polyethylene glycols having a melting point of 25° C. or above. The invention also provides a process of preparing a non-aqueous oral care composition as defined above, comprising the steps of forming a mixture comprising the thickening agent, the humectant, the liquid polyethylene glycol(s) and the solid polyethylene glycol(s), heating the mixture to a temperature above the melting point of the solid polyethylene glycol(s), and cooling the mixture to form crystals of the solid polyethylene glycol(s).
We have recognized a need to develop a non-aqueous oral care composition which is easy to manufacture, stable and/or has good consumer perception, and the present invention, therefore, is directed to a non-aqueous oral care composition comprising an organoclay, carrier humectant, and a calcium source. It is unexpectedly found that the non-aqueous oral care composition is easy to be manufactured without heating and cooling steps. The composition is surprisingly stable, cost-effective, and has suitable viscosity characteristics in absence of water.